Question

6. Solve for x and y:
question is from matrices chapter
plz don't scam​

Answer 1

$\implies\left[\begin{array}{cc}2&5\\5&2\end{array}\right] \left[\begin{array}{cc} \tt x\\ \tt \: y\end{array}\right] = \left[\begin{array}{cc} \tt - 7\\ \tt \: 14\end{array}\right]$

Now, we have to find out the value of x and y using above expression.

First we will have to multiple the left hand side.

$\implies \left[\begin{array}{cc} \tt 2x + 5y\\ \\ \tt \: 5x + 2y\end{array}\right] = \left[\begin{array}{cc} \tt - 7\\ \\ \tt \: 14\end{array}\right]$

Now , we will equate both sides.

=> 2x+5y = -7

=> 2x = -7-5y

=> x = (-7-5y)/2......(1)

=> 5x +2y = 14

=> 5x = 14 -2y

=> x = (14 -2y)/5......(2)

Form (1) and (2) we get :-

=> (-7-5y)/2 = (14 -2y)/5

Cross multiply :-

=> (-7-5y)×5 = (14 -2y)×2

=> (-7-5y)×5 = (14 -2y)×2

=> -35 -25y = 28 -4y

=> 4y-25y = 28 +35

=> -21y = 63

=> -y = 63/21

=> -y = 3

=> y = -3

Put y = -3 in equation (2) to find the value of x.

=> x = (14+6)/5

=> x = 20/5

=> x = 4

Answer :

• x = 4
• y = -3